Unless proven otherwise, the reference for building outlines in Belgium is numerical imagery. Our country is made of 3 Regions, each providing an accurate overview of buildings:

  • Brussels (UrbisAdm)
  • Flanders (Digitaal Vlaanderen GRB)
  • Wallonia (PICC numerical imagery)

Every day, we see new users moving or redrawing buildings after tracing them directly on aerial imagery, which is the default option in the iD editor.

Could you please make sure that this MapRoulette challenge will encourage people to check against numerical imagery and not aerial imagery?

To illustrate my point, here is a “spiky building” I drew today: Way: 1275225416 | OpenStreetMap It has a sharp dent, yet this is the official outline of the building. A user who traces on aerial imagery will only see the roof and might want to “fix” it.

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